Bridging and Switching Methods and Performance Issues.

Bridges operate by examining MAC layer addresses, using the destination and source addresses within a frame as a decision criterion to make their forwarding decisions. Operating at the MAC layer, bridges are not addressed, and must therefore examine all frames that flow on a network. A transparent bridge examines MAC frames to learn the addresses of stations on the network, storing information in internal memory in the form of an address table. One of the key advantages of a transparent bridge is that it operates independently of the contents of the information field and is protocol-independent.